An instrument package entering the water at very high rates (1500 to 2000 feet per second), was to be tracked on an acoustic range. An acoustic pinger was required that would survive the impact of water entry and provide tracking pings allowing tracking of the high speed instrument package. The program requires to know the path taken by the instrument package and its velocity after entry. A by-product of the successful tracking would locate the package on the bottom if the range tracks it to the bottom.
Acoustic pingers have been attached to some of the vehicles yet often times they do not survive the entry impact. Methods of mounting some acoustic pingers cause problems in themselves by reason of structural modifications in the entry vehicle.
Thus, there is a continuing need in the state of the art for an acoustic pinger capable of surviving a water entry impact and which requires no performance comprising modifications of the host vehicle.